Casing hangers are used to support casing from a casing head in a well bore. One disadvantage of prior casing hangers has been that they often exert the greatest force in the area of the pipe which is subjected to the greatest stress. The prior patent to Marvin R. Jones, U.S. Pat. No. 3,052,943, provided flexible gripping elements backed by a confined deformable part which acts as a quasi-liquid to transmit the gripping load from teeth nearest the load application to the teeth away from the load application. This structure tends to uniformly load the gripping elements.
Another type of gripping assembly has used individual pipe engaging elements or dogs which are held in a stack in a dove-tailed groove with an alloy steel backing plate behind the dogs. The knurled top half of the front edge of each dog contacts the pipe and the bottom half is beveled away to allow clearance when the dog is rolled upward. The top half of the back edge of each dog is relieved by rounding to permit the dog to roll upward and away from the pipe when the pipe is raised to facilitate release of the engagement of the dogs with the pipe. Such rolling dog type of gripping assembly does not include a variable area deformable backing in support of the gripping elements.